Heat-stable DNA polymerase of archaeobacteria of genus pyrococcus sp.

ABSTRACT

A purified thermostable DNA polymerase of archaeobacteria of the genus Pyrococcus sp. having a molecular weight of around 89,000-90,000 daltons is disclosed.

This application is a National Stage of International Application No. PCT/FR97/01259, filed on Jul. 10, 1997, and French Application No. FR96/08631, filed on Jul. 10, 1996, both of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to new thermostable DNA polymerases derived from archaeobacteria of the genus Pyrococcus sp.

BACKGROUND OF THE INVENTION

The DNA polymerases are enzymes involved in the replication and repair of DNA. There are currently numerous known DNA polymerases isolated from microorganisms such as E. [Escherichia] coli; for example, DNA polymerase I of E. coli, the Klenow fragment of DNA polymerase I of E. coli, DNA polymerase T4. Thermostable DNA polymerases are also identified and purified from thermophilic organisms, such as Thermus aquaticus (Chien, A., et al., J. Bacteriol. 1976, 127:1550-1557; Kaladin et al., Biokhymiyay 1980, 45:644-651), Thermus thermophilus, or else the species bacillus (European Patent Application No. 699,760), thermococcus (European Patent Application No. 455,430), sulfobus and pyrococcus (European Patent Application No. 547,359). Among these, it is possible to mention more particularly Pfu of Pyrococcus furiosus, the Vent DNA polymerase of Thermococcus litoralis (Kong, H. M., R. B. Kucera, and W. E. Jack, 1993, J. Biol. Chem. 268(3):1965-1975), 9°-NDNA polymerase of Pyrococcus sp., 9°-N, and Deep-Vent DNA polymerase of Pyrococcus sp. GB-D.

The replication process takes place according to a well-known mechanism comprising manufacturing (from a template, DNA polymerase enzyme and four triphosphate nucleotides) a strand of complementary nucleic acid of said template. The enzymes with DNA polymerase activity are currently widely used in vitro in numerous molecular biology processes, such as cloning, detection, labeling, and amplification of nucleic acid sequences.

Amplification of nucleic acid sequences by the method called polymerase chain reaction (PCR), described in the European Patent Nos. 200,362 and 201,184, is based on the execution of successive cycles of extensions of primers, using a DNA polymerase and the four triphosphate nucleotides, followed by denaturation of the double-strand nucleic acids thus obtained and used as templates for the next cycle. Since the temperatures used in the denaturation step are not compatible with preservation of the activities of numerous DNA polymerases, important research studies are dedicated to the thermostable enzymes described in the preceding. It is particularly essential not to limit the preparation of these enzymes solely to the processes of purification from microorganisms, but to seek to increase the production yields using methods of genetic engineering. According to these methods, which are well known to the experts in the field (Maniatis et al., Molecular Cloning: A Laboratory Manual, 1982), the gene coding for DNA polymerase is cloned in an expression vector, a vector which is inserted in a cellular host capable of expressing the enzyme, the cellular host is grown under suitable conditions, and the DNA polymerase is isolated and recovered. This method was described, for example, in the patent application PCT WO89/06691 for producing DNA polymerase of Thermus aquaticus.

SUMMARY OF THE INVENTION

The present invention relates to thermostable purified DNA polymerase of archaeobacteria of the genus Pyrococcus sp.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a Southern blot analysis revealing an 8-kb XbaI—XbaI positive fragment using probe PfuF.

FIG. 2 shows a Southern blot analysis revealing a 2.9-kb HindIII—HindIII positive fragment using a TliI probe labeled with ³²P.

FIG. 3 shows the different RFLP profiles of the genes of DNA polymerase of Pyrococcus sp. G 23 and G 5, obtained with the different probes (pFuΣ, PfuP, TliI).

FIG. 4 shows the phylogenetic tree of the DNA polymerases of Thermococcales.

FIG. 5 shows the phylogenetic situation of Pyrococcus sp. G 23 and Pyrococcus sp. GE 5 (Pyrococcus abyssi) based on the 16S rDNA sequences.

FIG. 6 represents the results of the expression tests, in which: Well No. 1 corresponds to the 10-kDA Ladder protein (Gibco BRL); Well No. 2 corresponds to the sample induced without IPTG, time 0 (exponential growth phase); Well No. 3 corresponds to the sample induced without IPTG, 1 h after induction; Well No. 4 corresponds to the sample induced without IPTG, 4 h after induction; Well No. 5 corresponds to the sample induced without IPTG, 18 h after induction; Well No. 6 corresponds to the 10-kd ladder protein (Gibco BRL); Well No. 7 corresponds to the sample induced with 1 mM IPTG, time 0 (exponential growth phase); Well No. 8 corresponds to the sample induced with 1 mM IPTG, 1 h after induction; Well No. 9 corresponds to the sample induced with 1 mM IPTG, 4 h after induction; and Well No. 10 corresponds to the sample induced with 1 mM IPTG, 18 h after induction.

FIG. 7 represents the elution profile of the sample consisting of 450 mL of soluble proteins after thermal denaturation at 75° C. obtained during purification of the DNA polymerase of Pyrococcus sp. GE 5.

FIG. 8 represents the analysis by SDS-PAGE (Phast System, Pharmacia), in the presence of β-mercaptoethanol, of different fractions coming from the purification of the DNA polymerase of Pyrococcus sp. GE 5.

FIG. 9 represents the elution profile for the sample consisting of 50 mL of the fraction containing the DNA polymerase of Pyrococcus sp. GE 5 (fraction 2) after ion-exchange chromatography.

FIG. 10 shows the 3 fractions obtained during purification of the DNA polymerase of Pyrococcus sp. GE 5 after chromatography using hydroxyapatite and analysis by SDS-PAGE in the presence of 2-mercaptoethanol.

FIG. 11 shows that fraction 1 contains the DNA polymerase of Pyrococcus sp. GE 5 homogenized by SDS-PAGE, while fractions 2 and 3 are contaminated by 2 35-kd and 65-kd proteins.

FIG. 12 represents the PCR products loaded on 2% agarose gel in the presence of the pBR marker digested by HaeIII obtained during purification of the DNA polymerase of Pyrococcus sp. GE 5.

FIG. 13 represents the PCR products loaded on 2% agarose gel in the presence of the pBR marker digested by HaeIII obtained during purification of the DNA polymerase of Pyrococcus sp. GE 5.

FIG. 14 shows the principles of inverse PCR (iPCR) and of the new method worked out with Pab, called high-temperature inverse PCR (HT-iPCR).

FIG. 15 represents the comparison of the results of iPCR and HT-iPCR using Taq and Pab: lane 1: “Raoul” marker; lane 2: HT-iPCR with Pab; lane 3: HT-iPCR with Taq; and lane 4: i PCR with Taq.

FIG. 16 represents PCR at high temperature (elongation at 85° C. using 30 cycles): lane 1: “Raoul” marker; lane 2: Pab; lane 3: Ppr; lane 4: control without DNA; and lane 5: Vent.

FIG. 17 shows DNA polymerase Pab activity at three temperatures 92° C., 95° C. and 100° C.

FIG. 18 shows DNA polymerase Ppr activity at three temperatures 92° C., 95° C. and 100° C.

FIG. 19 shows DNA polymerase Pab and Ppr activity after inactivation at 100° C.

FIG. 20 shows Pab, Ppr and Thermus aquaticus (Taq) polymerase activity after inactivation at 92° C.

The development of recombinant DNA technologies in the field of research as well as in that of industrial production requires one to have various DNA polymerases capable of improving quantitatively or qualitatively, techniques as diverse as cloning, detection, labeling, or amplification of nucleic acid sequences.

The present invention aims precisely to offer new hyperthermostable enzymes obtained from Pyrococcus sp. species which catalyze the polymerization of DNA. These enzymes come from isolates of samples of hyperthermophilic archaeobacteria (Woese, C. R., O. Kandler, and M. Wheelis, 1990, Proc. Natl. Acad. Sci. USA 87:4576-4579) taken from deep hydrothermal springs of the North-Fiji basin in the south Pacific (Desbruyeres, D., A.-M. Alayse-Danet, and S. Ohta, 1994, Geology 116:227-242; Marteinsson, V. T., L. Watrin, D. Prieur, J. C. Caprais, G. Raguenes, and G. Erauso, 1995, International Journal of Systematic Bacteriology 45(4):623-632). All these isolates are hyperthermostable with isolation temperatures on the order of 80 to 100° C. A DNA polymerase of the invention has a molecular weight of approximately 89,000 d and has a hyperthermostability which enables it to be used in reactions conducted at temperatures of 70-90° C.

The studies performed in the context of the invention made it possible to identify two new thermostable DNA polymerases of archaeobacteria of the genus Pyrococcus sp. whose phylogenetic relationship was studied. The genes coding for these two DNA polymerases were cloned and sequenced, and their comparison revealed great similarities of sequence and organization.

The invention relates more particularly to a thermostable purified DNA polymerase of archaeobacteria of the genus Pyrococcus sp. which has a molecular weight between approximately 89,000 and 90,000 d.

A first thermostable purified DNA polymerase according to the invention comes from the strain of archaeobacteria of the genus Pyrococcus sp. filed in the National Microorganism Culture Collection (CNCM) at the Pasteur Institute, Jul. 3, 1996 under the No. I-1764. This DNA polymerase will subsequently be called Pyrococcus sp. GE 23. Its sequence of 771 amino acids is represented in the appended sequence list under the number SEQ ID NO:2. A molecular weight of 89,409 d and a pI of 8.37 were deduced from this sequence. The invention relates then to the DNA polymerase of Pyrococcus sp. GE 23 whose amino acid sequence is represented in the appended sequence list under the number SEQ ID NO:1 or any other sequence constituting a derivative which is enzymatically equivalent to it. Enzymatically equivalent derivatives are understood to mean the polypeptides and proteins comprising or including the amino acid sequence represented in the appended sequence list under the number SEQ ID NO:2 when they have the properties of the DNA polymerase of Pyrococcus sp. GE 23. On this basis, the invention more particularly envisages a DNA polymerase whose amino acid sequence is a fragment of that represented in the appended sequence list under the number SEQ ID NO:2 or else an assemblage of such fragments.

Enzymatically equivalent derivatives are also understood to mean the amino acid sequences above modified by insertion and/or deletion and/or substitution of one or more amino acids, in as much as the resulting properties of the DNA polymerase of Pyrococcus sp. GE 23 are not significantly modified.

A second thermostable purified DNA polymerase according to the invention comes from the strain of archaeobacteria of the genus Pyrococcus sp. filed in the CNCM, Apr. 20, 1993 under the No. I-1302. This DNA polymerase will subsequently be called Pyrococcus sp. GE 5 (otherwise known as Pyrococcus abyssi). Its sequence of 771 amino acids is represented in the appended sequence list under the number SEQ ID NO:4. A molecular weight of 89,443 d and a pI of 8.13 were deduced from this sequence.

The invention relates then to the DNA polymerase of Pyrococcus sp. GE 5 whose amino acid sequence is represented in the appended sequence list under the number SEQ ID NO:4 or any other sequence constituting a derivative which is enzymatically equivalent to it. Enzymatically equivalent derivatives are understood to mean the polypeptides and proteins comprising or including the amino acid sequence represented in the appended sequence list under the number SEQ ID NO:4 when they have the properties of the DNA polymerase of Pyrococcus sp. GE 5. On this basis, the invention more particularly envisages a DNA polymerase whose amino acid sequence is a fragment of that represented in the appended sequence list under the number SEQ ID NO:4 or else an assemblage of such fragments.

Enzymatically equivalent derivatives are also understood to mean the amino acid sequences above modified by insertion and/or deletion and/or substitution of one or more amino acids, in as much as the resulting properties of the DNA polymerase of Pyrococcus sp. GE 5 are not significantly modified.

The DNA polymerases of Pyrococcus sp. GE 23 and of Pyrococcus sp. GE 5 are distinguished from one another by 10 amino acid residues whose positions are indicated in Table I below.

TABLE 1 Positions Pyrococcus sp. GE 23 Pyrococcus sp. GE 5 263 Val Ala 277 Ala Thr 281 Ala Val 320 Phe Ser 339 Gln His 359 Arg Thr 391 Lys Asn 532 Ser Arg 553 Pro His 554 Asn Glu

The invention also relates to a DNA sequence comprising the sequence coding for a thermostable purified DNA polymerase according to the invention.

A first DNA sequence according to the invention comprises the nucleotides 1547 to 3862 of SEQ ID NO:1 coding for the 771 amino acids of the DNA polymerase of Pyrococcus sp. GE 23.

A second DNA sequence according to the invention comprises the nucleotides 678 to 2994 of SEQ ID NO:3 coding for the 771 amino acids of the DNA polymerase of Pyrococcus sp. GE 5.

The invention relates as much to the thermostable DNA polymerase defined in the preceding isolated and purified from a strain of Pyrococcus sp. as to the thermostable DNA polymerase prepared by the methods of genetic engineering. Consequently, the invention also relates to a vector which includes a DNA sequence defined in the preceding, as well as to a process for production or expression in a cellular host of the thermostable DNA polymerases of the invention.

A process for production of a thermostable DNA polymerase according to the invention comprises:

of transferring a molecule of nucleic acid coding for a thermostable DNA polymerase or a vector containing said molecule into a cellular host,

of growing the cellular host obtained in the preceding step under conditions making possible the production of the DNA polymerase,

of isolating said DNA polymerase by any suitable means.

The cellular host used in the preceding processes can be chosen from the prokaryotes or the eukaryotes and particularly from bacteria, yeasts, and from cells of mammals, plants or insects.

The vector used is chosen as a function of the host into which it will be transferred; it can be any vector such as a plasmid.

The thermostable DNA polymerases of the invention can be used particularly in processes of enzymatic amplification of nucleic acid sequences. Consequently, the invention relates to such processes using a thermostable DNA polymerase described in the preceding as well as to the amplification kits which contain a suitable quantity of this DNA polymerase besides the reagents which are generally used.

Other advantages and characteristics of the invention will appear upon reading of the following examples given on a nonlimiting basis and relating to the cloning, expression, characterization, and activity of the thermostable DNA polymerases of the invention.

I Materials and Methods

1) Culture Conditions, Plasmids, and Strains Used

The strains Pyrococcus furiosus (DSM 5262) and Thermococcus litoralis (DSM 5474) were obtained from the collection of the German Collection of Microorganisms (DSM) Braunschweig—Stocheim, Germany. The strains Pyrococcus sp. G 23 and G 5 were isolated from vents of deep hydrothermal springs discovered in the Starmer Franco-Japanese campaign occurring in 1989 at 2000 m depth in the North-Fiji basin.

Pyrococcus sp. G 5 was grown anaerobically in an 8-L fermenter in BHI medium (Difco) supplemented with sulfur at a pH of 6.5 and at 90° C., as described in the literature (Erauso, G., A. L. Reysenbach, A. Godfroy, J.-R. Meunier, B. Crump, F. Partensky, J. A. Baross, V. Marteinsson, G. Barbier, N. R. Pace and D. Prieur, 1993, Arch. Microbiol. 160:338-349).

Pyrococcus sp. G 23 was grown at 85° C. in an identical fermenter in 2216S medium (Difco) at a pH of 6.5.

The strain E. coli SURE, XL-1-Blue (Stratagene, LaJolla, Calif. USA) was used as host for the recombinant plasmids from pUC18 and pBluescript. The strains E. coli NOVABLUE, BL21(DE3), and BL21(DE3)pLysS (Novagen, Madison, Wis. USA) were used as hosts for the derived recombinant plasmids. E. coli SURE, XL1-Blue, NOVABLUE, BL21(DE3), and BL21(DE3)pLysS were grown,in LB medium (Difco) or LB medium (Difco) supplemented with appropriate antibiotics.

2) Isolation of the DNA, Hybridization, and Recombinant DNA

The high-molecular-weight DNA of Pyrococcus sp. G 23 and G 5 was isolated by the modified Charbonnier method (Charbonnier, F., G. Erauso, T. Barbeyron, D. Prieur, and P. Forterre, 1992, J. Bacteriol. 174(19):6103-6109). The centrifuged cells were resuspended in TE-Na-1×buffer, then lysed at 40° C. for 3 h with a mixture of N-lauryl sarcosine 1%, sodium dodecyl sulfate 1% and 0.4 mg/mL of proteinase K. After centrifugation at 5000 G for 10 min, the DNA is extracted by PCI (25-24-1), and then treated with RNAase at a concentration of 5 μg/mL at 60° C. for 1 h. These steps are followed by an additional extraction with PCI and chloroform extraction. The DNA is precipitated with 100% ethanol, and the pellets are dried and suspended in TE-1×. The concentration and purity of the DNA were estimated by spectrophotometry at 230, 260, and 280 nm with a GeneQuantII apparatus (Pharmacia, Upsalla, Sweden). For the construction of the pUC18 minilibrary (Sutherland, K. J., C. M. Henneke, P. Towner, and D. W. Hough, 1990, European J. Biochem., 194:839-844) of Pyrococcus sp. G 23, the genomic DNA was digested by a series of restriction enzymes (BamHI, Bg[l]II, EcoRI, EcoRV, HindIII, PvuII, SaII, SacI, XbaI, and XhoI) by single or double digestion. Then, the DNA fragments underwent a migration on 0.8% agarose gel in TBE-1× and were transferred onto Hybond-N+nylon membrane (Amersham, UK) and hybridized with DNA probes prepared by PCR with specific primers selected from genes of DNA polymerase of P. furiosus and T. litoralis, labeled with ³²P by random-priming according to the recommendations of the manufacturer (Magaprime, Amersham, UK). Two probes of P. furiosus were used, pFuΣ and PfuF, respectively covering the regions delimited by the base pairs 8-2316 and 819-1915 of the coding region of the polymerase Pfu gene, as defined by Uemori et al. (Uemori, T., Y. Ishino, H. Toh, K. Asada, and I. Kato, 1993, Nucleic Acids Res. 21(2):259-265). Two probes of T. litoralis were used, TliI and TliT, respectively covering the regions delimited by the base pairs 297-1768 and 4631-5378, as defined by Hodges et al. (Hodges, R. A., F. B. Perler, C. J. Noren, and W. E. Jack, 1992, Nucleic Acids Res. 20(23):6153-6157). The positive fragments, identified by DNA—DNA hybridization (Southern, E. M., 1975, Journal of Molecular Biology, 98:503), were then prepared by appropriate digestions of 100 μg of genomic DNA, purified using agarose gels in dialysis bags, and precipitated with 100% ethanol. The fragments were ligated in pUC18, which had been cut by appropriate restriction enzymes for a single and dephosphorylated digestion. The transformation of the host strains was done by electroporation (Gene Pulser, Biorad). The screening of the recombinant clones was done by colony hybridization according to the techniques described in the literature (Sambrook, J., E. F. Fritsch, and T. Maniatis, 1989, Molecular Cloning: A Laboratory Manual, 2nd ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor). The temperature of the Southern blots and of colony hybridization was 55° C. in a standard buffer without formamide. The plasmid DNA was isolated by the method of Bimboim and Doly (Bimboim, H. C., and J. Doly, 1979, Nucleic Acids Res., 7:1503), then purified by solid-phase anion-exchange chromatography (Quiagen, Chatsworth, Calif. USA). The restriction fragments of the plasmids derived from pUC were purified using agarose gels by the GeneClean method (Bio 101, LaJolla, Calif.) for later cloning. The polymerization chain reactions (PCR) of long fragments were carried out according to the procedure defined by Barnes (Barnes, W. M., 1994, Proc. Natl. Acad. Sci. USA 91:2216-2220) with a Taq Extender reaction mixture (Stratagene, LaJolla, Calif.). The rDNA of 16S and 23S of Pyrococcus sp. GE 23 were amplified by PCR with a Stratagene 96-well thermocycler using the following conditions:

direct primer Aa (5′-TCCGGTTGATCCTGCCGGA-3′)(SEQ ID NO:5),

indirect primer 23Sa (5′-CTTTCGGTCGCCCCTACT-3′)(SEQ ID NO:6),

initial step 3 min at 94° C. followed by 30 cycles (94° C., 1 min/49° C., 1 min/72° C., 2 min) and,

final elongation of 5 min at 72° C.

The PCR products were cloned in the vector pBluescript for sequencing.

The gene of the DNA polymerase of Pyrococcus sp. GE 5 was isolated by PCR using the primers developed for expressing the gene of the DNA polymerase of Pyrococcus sp. GE 23:

5′-TGGGGCATATGATAATCGATGCTGATTAC-3′(SEQ ID NO:7)

5′-GACATCGTCGACTCTAGAACTTAAGCCATGGTCCG-3′(SEQ ID NO:8)

3) Sequencing of the DNA

The DNA sequences were obtained by the dideoxy chain termination method (Sanger, F., S. Nicklen, and A. R. Coulson, 1977, Proc. Natl. Acad. Sci. USA 74:5467-5473) using an Applied Biosystems automatic DNA analysis system. The two strands of the genes coding for the DNA polymerase of Pyrococcus sp. G 23 and G 5 were sequenced, while the 16S rDNA of Pyrococcus sp. G 23 was sequenced on a single strand, using universal primers located on vectors and internal primers.

The sequence analysis was done with DNASTAR software (Madison, Wis., USA), and the Genetics Computer Group program (University of Wisconsin Biotechnology Center, Madison, Wis., USA) which is accessible on-line using INFOBIOGEN. The computerized similarity searches were done with the BLAST program, the multiple alignments with CLUSTAL V, and the phylogenetic trees were established according to the method called “neighbor-joining” (Saitou, N. and M. Nei, 1987, Mol. Biol. Evol. 4(4):406-425).

4) Construction of the Recombinants Expressing the DNA Polymerase of Pyrococcus sp. G 23 and G 5

The DNA polymerases of Pyrococcus sp. G 23 and G 5 were expressed in E. coli using the pET12 expression system, belonging to the T7 expression system (Studier, F. W., A. H. Rosenberg, F. J. Dunn, and J. W. Dubendorff, 1990, Methods Enzymol. 185:60-89) purchased from Novagen (Madison, Wis., USA). PCR was used to prepare the fragments of Pyrococcus sp. G 23 and G 5 containing the restriction sites NdeI and SalI which are compatible with the ends of primers GE23DIR and GE23REV. The PCR mixture contained Goldstar DNA polymerase (Eurogentec, B), the Taq-extended Taq enzyme (Pfu of Stratagene), the extension buffer with the four dNTP (each at 0.2 mM) and the primers GE23DIR and GE23REV at a concentration of 50 pmol in a final volume of 50 μL. The amplification was done over 20 cycles: 1 min at 90° C., 1 min at 50° C. and 3 min at 72° C., using a Stratagene 96-well thermocycler. The PCR fragments digested by NdeI and SalI were ligated to the sites NdeI and SalI of pET12a which were digested by the same enzymes, thus reestablishing the initiation codon. The constructions obtained were respectively named pETPAB1 and pETGE1. These constructions were both sequenced at the junction sites and entirely in the case of pETPAB1. The expression tests were carried out according to the recommendations of the manufacturer of the pET expression system: Selection of the clones in E. coli Novablue, culture of E. coli BL21(DE3), induction (IPTG 0.2-1 mM).

750 μL of cells of OD₆₀₀=1 induced and noninduced cultures were centrifuged, resuspended in lysis buffer B (Tris HCl 10 mM pH 7.5; NaCl 10 mM; MgCl₂ 2 mM; Triton X-100 1% vol/vol). The DNA polymerase was observed by SDS-PAGE after a partial thermal denaturation of the host proteins (71° C., 20 min) and concentrated using Millipore filters (Ultrafree MC). The activity was tested by measurement of the incorporation of ³H-dTTP (Amersham, UK) using activated calf thymus DNA as substrate (Sigma-Aldrich, F) in reaction medium C (Tris HCl 50 mM pH 8.8; DTT 1 mM; MgCl₂ 10 mM; KCl 10 mM; BSA 0.4 mg/mL, each dNTP at 0.4 mM).

II Results

1) Isolation of the Gene of the DNA Polymerase of Pyrococcus sp. GE 23

The genomic DNAs of the strains Pyrococcus sp. GE 23 and GE 5, digested by a series of restriction enzymes, were hybridized with the DNA of P. furiosus and with probes of T. litoralis prepared by PCR. As shown in FIGS. 1 and 2, the Southern blot analyses revealed a 2.9-kb HindIII—HindIII positive fragment with a TliI probe labeled with ³²P (FIG. 2), whereas probe PfuF revealed an 8-kb XbaI—XbaI positive fragment (FIG. 1) (24-h exposure). The 2.9-kb fragment was isolated and purified as described in the preceding Materials and Methods section and cloned into the vector pUC18 digested by HindIII. Approximately 600 recombinants (E. coli SURE) were screened with a radioactively labeled TliI probe, and 6 of them gave a positive hybridization signal. Identical restriction profiles were obtained for these clones, indicating that they probably contained the same insert. The later sequencing of one of these clones (designated pGE23a) and the sequence comparison (FASTA) demonstrated that it corresponds to the first 1358 base pairs of the gene of the DNA polymerase belonging to family B (Braithwaite, D. K., and J. Ito, 1993, Nucleic Acids Res. 21(4):787-802) and that it ends with the HindIII site. The analysis of the nucleotide sequence shows that the XbaI site is located upstream from the initiation codon and that consequently, the 8-kb XbaI—XbaI positive fragment should contain the 3′ part of the gene. According to the same method, this 8-kb fragment was cloned into vector pUC18, and 3 positive recombinant clones out of 800 were identified by colony hybridization as in the preceding using a homologous probe prepared from the 5′ part of the gene of the DNA polymerase of Pyrococcus sp. GE 23. The cultures of these clones in a liquid medium (LB-ampicillin) were systematically lysed well before OD₆₀₀=0.5. One culture was stopped at OD₆₀₀=0.1, and the plasmid DNA (designated pGE23b) was extracted. The long distance PCR (with the Taq Extender) was performed on this plasmid DNA using a direct primer located on the 5′ part of the sequence obtained in the preceding and a reverse primer located downstream on the vector pUC18, in order to obtain an 8-kb amplification product. The 3′ part was sequenced later. Then, another long distance PCR was done using the same direct primer located on the 5′ part of the gene and a reverse primer located on the available 3′ part. The amplification products of 10 separate PCR reactions were collected, purified by electrophoresis using agarose gel and sequenced on the two strands using internal primers. These products contain the 3′ part of the gene of the DNA polymerase of Pyrococcus sp G 23.

2) Phylogenetic Position of Pyrococcus sp. G 23 and G 5

Pyrococcus sp. G 23 and G 5 belong to the same 16S rDNA PCR-RFLP group (Meunier, J. R., 1994, Biodiversity and systematics of populations of thermophilic microorganisms isolated from abyssal oceanic hydrothermal ecosystems. Thesis, Paris 7), indicating that they could be two different strains of the same species. However, as shown in FIG. 3, the different RFLP profiles of the genes of DNA polymerase of Pyrococcus sp. G 23 and G 5, obtained with the different probes (pFuΣ, PfuP, TliI) indicate that at least the genes of the DNA polymerase have significant differences. Slot blot DNA-DNA hybridizations (Marteinsson, V. T., L. Watrin, D. Prieur, J. C. Caprais, G. Raguenes, and G. Erauso, 1995, Int. J. Systemat. Bacteriol. 45(4):623-632) led to contradictory relationship levels: 79% between unlabeled GE 23 and labeled GE 5, and 98% between unlabeled GE 5 and labeled GE 23. The amplification of the genes of the 16S-23S rDNA was done as described in the preceding in Materials and methods. The 1.9-kb amplified band was purified and sequenced on one strand. The complete 16S rDNA sequence was compared with its counterpart of Pyrococcus sp. GE 5 and of other species of Pyrococcus sp. and thermococcus. The level of similarity between Pyrococcus sp. GE 23 and Pyrococcus sp. GE 5 is 97.8%, and Pyrococcus sp. GE 23 was regrouped with Pyrococcus sp. GE 5 (Pyrococcus abyssi) in the phylogenetic tree of the DNA polymerases of Thermococcales of FIG. 4. Likewise, FIG. 5 represents the phylogenetic situation of Pyrococcus sp. G 23 and Pyrococcus sp. GE 5 (Pyrococcus abyssi) based on the 16S rDNA sequences. In these two figures, the dendrogram was established by the “neighbor-joining” method, and the scale represents the relative distance between the sequences.

3) Identification of the Gene of the DNA Polymerase of Pyrococcus sp. GE 5

Deducing from the relationship between these two strains that the direct isolation of the gene of the DNA polymerase of Pyrococcus sp. GE 5 was possible by PCR, the two primers GE23DIR and GE23REV, prepared for cloning the gene of the DNA polymerase of Pyrococcus sp. GE 23 in the vector pET12, were used in a PCR reaction containing the genomic DNA of Pyrococcus sp. GE 5. The amplification products of 5 PCR reactions were collected, purified; and sequenced on the two strands. The nucleotide sequence has a strong homology (97%) with the gene of the DNA polymerase of Pyrococcus sp. GE 23. In order to obtain the sequence of the gene of the DNA polymerase of Pyrococcus sp. GE 5, different cloning tests were done. First of all, a 2.9-kb HindIII—HindIII fragment, identified by DNA—DNA hybridization, as shown in FIG. 3, was cloned into the vector pUC18, transformed into E. coli SURE and sequenced. It shows itself to be homologous to the 2.9-kb HindIII—HindIII fragment of Pyrococcus sp. GE 23 cloned in the preceding and containing the 5′ part of the target gene. Secondly, a 2.6-kb XbaI—XbaI positive fragment, potentially containing all of the coding region, was identified by DNA—DNA hybridization using the gene of the DNA polymerase of Pyrococcus sp. GE 5 produced by PCR as a radio labeled probe. This fragment was cloned in the vectors pUC18, pBluescript, and pET12 and transformed in E. coli Novablue (strain recA⁻). Three positive recombinant clones out of 600 were obtained with pET12 and none were obtained with pUC18 and pBluescript. The restriction profiles of the pET12 recombinant clones demonstrate that the integrity of the construction was not preserved. FIG. 3 shows that the major part of the insert was deleted in the process, and only the 342-bp HindIII-XbaI 3′ fragment remains. The definitive sequence of the gene of the DNA polymerase of Pyrococcus sp. GE 5 is composed of an HindIII—HindIII genomic 5′ part, a 611-bp HindIII—HindIII internal region coming from PCR products, and the genomic 342-bp 3′ part.

4) Nucleotide and Polypeptide Sequences of the DNA Polymerases of Pyrococcus sp. GE 23 and GE 5.

a) DNA Polymerase of Pyrococcus sp. GE 23

The 2.9-kb HindIII—HindIII Pyrococcus sp. GE 23 fragment which was cloned, as well as a contiguous 1.6-kb fragment in the 3′ direction obtained by long distance PCR, were sequenced on the two strands and assembled. The 4447-bp sequence obtained was studied in order to determine the regions capable of being translated. Two open reading frames were revealed. The first, in frame 2, extending from the base pair 1547 to the base pair 3862, corresponds to the gene of the DNA polymerase coding for a protein with 771 amino acids, whose molecular weight deduced from the sequence is 89,409 D and whose theoretical isoelectric point is 8.37. This molecular weight corresponds to the apparent molecular weight estimated by SDS-PAGE of the recombinant DNA polymerase. The second ORF was located on frame 4 between the base pairs 1439 and 627.

The deduced sequence has a length of 270 amino acids and the similarity searches done with the programs BLAST and FASTA did not reveal any significant homology with the available sequences in the Swiss-Prot and PIR databases.

b) DNA Polymerase of Pyrococcus sp. GE 5

The complete coding sequence of the gene of the DNA polymerase of Pyrococcus sp. GE 5 produced by PCR using the primers prepared from the gene of Pyrococcus sp. GE 23 was obtained by sequencing the two strands. In order to confirm the sequence of this PCR product, the 2.9-kb HindIII—HindIII Pyrococcus sp. GE 5 fragment cloned was also sequenced on the two strands, and the same results were obtained. The 3′ region of the gene was also sequenced from the remaining 342-bp HindIII-XbaI insert resulting from the deletion of a part of the 2.6-kb XbaI—XbaI fragment. Only the 611-bp HindIII—HindIII internal region of the sequence of the gene obtained from the PCR products could not be confirmed at the genomic level. An open reading frame between base pairs 679 and 2994 was identified, whose translation produces a polypeptide sequence of 771 amino acids, length which is identical to that of the DNA polymerase of Pyrococcus sp. GE 23.

c) Comparison of the Sequences of the Two Polymerases

The alignment of the coding regions of the two genes shows their strong relationship since they only differ by 64 nucleotides dispersed along the sequences with two exceptions. First of all, one observes 14 substitutions between base pairs 1541 and 1603, making this region the most variable of the whole sequence; then one observes a limited number of substitutions in the 3′ region between base pairs 1890 and 2316. The majority of these substitutions have no consequence with regard to the polypeptide sequences; particularly the first 23 substitutions have no effect on the protein composition. The comparison with other genes of DNA polymerases of thermococcales which are available in the databases reveal that the highly variable region between base pairs 1541 and 1603 of Pyrococcus sp. GE 23 and GE 5 seems to be a characteristic of these two strains, the diversity being well distributed over the other sequences of genes coding for DNA polymerases. The comparison with regard to the polypeptide sequences shows the great similarity of the two DNA polymerases, 98% homology with the CLUSTAL V method, and only 10 different residues. The amino acid substitutions are given in Table I.

Table II below indicates the percentage of similarities between the polypeptide sequences of:

(1) Pyrococcus sp. GE 23, (2) Pyrococcus sp. GE 5,

(3) Pyrococcus sp. GB-D, (4) Pyrococcus sp. KOD1,

(5) Pyrococcus furiosus, (6) Thermococcus litoralis,

(7) Pyrococcus sp. 9° N.

TABLE II (1) (2) (3) (4) (5) (6) (7) *** 98,6 89,2 81,3 83,5 76,3 81,5 (1) *** 88,4 80,6 82,8 75,5 80,9 (2) *** 81,6 85,1 77,1 83,0 (3) *** 79,2 78,1 90,4 (4) *** 74,0 80,1 (5) *** 77,0 (6) *** (7)

The majority of the amino acid substitutions between the DNA polymerases of Pyrococcus sp. GE 23 and GE 5 are nonconserved, but none is located in units known to be involved in the catalytic action of the enzyme, or in the exonuclease or polymerase 3′-5′ domains. The two genes have no intron sequence (IVS or inteines) contrary to the genes of DNA polymerase of T. litoralis, Thermococcus sp. KOD1, Pyrococcus sp. GG-D, and have the same organization as the genes of DNA polymerase of P. furiosus and Pyrococcus sp. 9° N.

5) Expression, Characterization, and Activity of the DNA Polymerase of Pyrococcus sp. GE 5

a) Cloning and Expression

A 2320-bp insert covering the 2316-bp DNA sequence of SEQ ID NO:1 coding for the DNA polymerase of Pyrococcus sp. GE 5 was cloned at the sites NdeI and BamHI of a vector in order to transform the E. coli strain BL21(DE3). Minipreparations of plasmid DNA were produced using approximately twenty transforming clones, and a single one was selected based on the size of the DNA fragments released after digestion by the NdeI and BamHI restriction enzymes.

Expression tests were then done at 37° C., in Erlenmeyer flasks, with the selected clone. The expression is induced in exponential growth phase (OD 600 nm=0.6-0.7) with IPTG concentrations of 0, 0.5, 1, and 1.5 mM. Samples are removed at different times in the course of the culture, and the proteins are analyzed by electrophoresis using acrylamide gel and with Coomassie blue. FIG. 6 represents the results of the expression tests, in which:

Well No. 1 corresponds to the 10-kDA Ladder protein (Gibco BRL).

Well No. 2 corresponds to the sample induced without IPTG, time 0 (exponential growth phase).

Well No. 3 corresponds to the sample induced without IPTG, 1 h after induction.

Well No. 4 corresponds to the sample induced without IPTG, 4 h after induction.

Well No. 5 corresponds to the sample induced without IPTG, 18 h after induction.

Well No. 6 corresponds to the 10-kd ladder protein (Gibco BRL).

Well No. 7 corresponds to the sample induced with 1 mM IPTG, time 0 (exponential growth phase).

Well No. 8 corresponds to the sample induced with 1 mM IPTG, 1 h after induction.

Well No. 9 corresponds to the sample induced with 1 mM IPTG, 4 h after induction.

Well No. 10 corresponds to the sample induced with 1 mM IPTG, 18 h after induction.

One observes that only the cells grown in the absence of IPTG express the DNA polymerase, and the level is maximum after a night of culture. The molecular weight of the expressed protein is estimated at 89 kd.

b) Fermentation and Extraction of the Cells

The culturing of the strain Pyrococcus sp. GE 5 was done according to a standard protocol. One added the selection factor for the plasmid to the R12 medium chosen for the preculture and the culture. The transfer of the preculture to the fermenter was done when the optical density at 600 nm of the preculture was approximately 0.8. The NBS MICROS fermenter (25 L) was used for this production, with a culture volume of 24 L. The fermentation conditions were as follows: Temperature=37° C.; shaking=300 rpm; aeration=30 L/m; dissolved oxygen=15%. The pH was adjusted to 6.8 with NaOH during the acidification phase. During the basification phase, the pH was allowed to change freely. The bacteria were collected [after] around 16-17 h of culture. The final optical density was approximately 10 units, and the final pH was 8. The culture was then concentrated by filtration using hollow fibers (Amicon), until a final volume of 2 L was obtained. This concentrate of bacteria was then used for the purification of the proteins. After cell concentration, the cells are ground continuously by means of a ball mill, and the ground cell product receives the addition of PMSF 1 mM.

c) Purification of the DNA Polymerase of Pyrococcus sp. GE 5

After centrifugation of the ground cell product (15 min at 10,000 G), the supernatant (soluble fraction) is recovered and heated for 15 min at 75° C. The precipitate which forms after thermal denaturation is eliminated by centrifugation (15 min at 10,000 G). The supernatant is loaded on an anion-exchange column:

Matrix Q Sepharose Fast Flow in an XK 16/30 column (Pharmacia).

Chromatographic system: Bio Pilot (Pharmacia).

Buffer A: Tris HCl 50 mM, pH 8 and buffer B: Tris HCl 50 mM, pH 8+NaCl 0.5M.

Flow rate: 10 mL/min; gradient 0-50% B over 60 min.

Fractions: 10 mL/tube.

FIG. 7 represents the elution profile of the sample consisting of 450 mL of soluble proteins after thermal denaturation at 75° C.

FIG. 8 represents the analysis by SDS-PAGE (Phast System, Pharmacia), in the presence of β-mercaptoethanol, of different fractions coming from the purification:

Gels: Phast gel 8-15% (Phast System, Pharmacia).

Lanes 1 and 8: molecular weight marker (10 kd, Bio-Rad).

Lane 2: Total proteins.

Lane 3: soluble proteins after grinding.

Lane 4: soluble proteins after thermal denaturation.

Lanes 5, 6, and 7: fractions 1, 2, and 3 after chromatography using QFF of FIG. 2.

As illustrated by FIG. 8, the DNA polymerase of Pyrococcus sp. GE 5 is soluble and thermostable. It is eluted towards 0.15 M NaCl in the ion exchange chromatography. The fractions containing the DNA polymerase of Pyrococcus sp. GE were collected (fraction 2; 50 mL) and subjected to chromatography using hydroxyapatite (type II, Biorad):

Matrix: hydroxyapatite type II in a 10/5 column (Biorad).

Chromatographic system: FPLC (Pharmacia).

Buffer A: Phosphate 50 mM pH 8; buffer B: Phosphate 500 mM pH 8.

Flow rate: 10 mL/min; gradient 0-100% B over 30 min.

FIG. 9 represents the elution profile for the sample consisting of 50 mL of fraction 2 after ion-exchange chromatography. The different fractions were analyzed by UV spectrometry and by SDS-PAGE. The nonabsorbed fraction mainly contains nucleic acids, whereas the fractions 1 to 3 contain the DNA polymerase of Pyrococcus sp. GE 5. After chromatography, 1 mM of [β-]mercaptoethanol, 0.1% Tween 20 and 50% glycerol were added before storage at −20° C.

d) Characterization of the Purified Fractions

The 3 fractions obtained after chromatography using hydroxyapatite were analyzed by SDS-PAGE in the presence of 2-mercaptoethanol (FIG. 10):

Gels: gel 15% (Laemli, Babygel).

Lanes 1 and 5: Molecular weight marker (Biorad, Broad Range).

Lane 2: Fraction 1 (5 μL).

Lane 3: Fraction 2 (5 μL).

Lane 4: Fraction 3 (5 μL).

Lane 6: Fraction 1 (10 μL).

Lane 7: Fraction 2 (10 μL).

Lane 8: Fraction 3 (10 μL).

As illustrated by FIG. 10 and in FIG. 11, fraction 1 contains the DNA polymerase of Pyrococcus sp. GE 5 homogenized by SDS-PAGE, while fractions 2 and 3 are contaminated by 2 35-kd and 65-kd proteins.

e) Activity of the Purified Fractions

The activity of DNA polymerase of the different fractions was tested in a PCR-type amplification reaction. An approximately 1300-bp fragment was amplified using a target DNA and specific primers. The buffer used is composed of:

Tris HCl: 75 mM pH 9.0.

(NH₄)₂SO₄: 20 mM.

0.01% (wt/vol) Tween 20.

MgCl₂: 1.5 mM.

Thirty-five cycles were done, each including a denaturation step of 1 min at 94° C., a step of pairing of the oligonucleotides of 1 min at the appropriate temperature, and an elongation step of 3 min at 72° C. FIG. 11 reports the results obtained with a reaction volume of 100 μL for quantities of DNA polymerase of Pyrococcus sp. GE 5 of 2.5 μg, 1 g, 0.1 g, and 0.01 μg:

Well No. 1: 1-kb ladder DNA (Gibco BRL).

Well No. 2: fraction 1 (2.5 μg).

Well No. 3: fraction 1 (1 μg).

Well No. 4: fraction 1 (0.1 μg).

Well No. 5: fraction 1 (0.01 μg).

Well No. 6: fraction 2 (2.5 μg).

Well No. 7: fraction 2 (1 μg).

Well No. 8: fraction 2 (0.1 μg).

Well No. 9: fraction 2 (0.1 μg).

Well No. 10: fraction 3 (2.5 μg).

Well No. 11: fraction 3 (1 μg).

Well No. 12: fraction 3 (0.1 μg).

Well No. 13: fraction 3 (0.01 μg).

Well No. 14: 1-kb ladder DNA (Gibco BRL).

Well No. 15: Positive control with Taq polymerase.

6) Conditions of Optimization of the PCR for the Polymerases of the Invention

In order to simplify the disclosure of the results hereafter and of the figures relating to them, the thermostable DNA polymerases of Pyrococcus abyssi (Pyrococcus sp. GE 5) and Pyrococcus sp. GE 23 will be respectively designated hereafter as Pab and Ppr.

PCR tests were performed under the following conditions:

10 mM Tris HCl, pH 9.0

50 mM KCl

3 mM MgSO₄

0.1% Tween

0.312 mM of each dNTP

50 mol of each oligonucleotide with formula:

5′TCACCTTAGGGTTGCCCATAA3′(SEQ ID NO:9)

5′TGGGCATAAAAGTCAGGGCAG3′(SEQ ID NO:10)

1 U of Pab (FIG. 12) or of Ppr (FIG. 13)

Increasing quantity of human genomic DNA of β-globin (from 0.5 ng to 3 μg); reaction volume: 50 μL.

The following PCR program was used:

5 min at 93° C.

37 times (1 min at 62° C.; 2 min at 72° C.; 1 min at 91° C.)

1 min at 62° C.

10 min at 72° C.

FIGS. 12 and 13 represent the PCR products loaded on 2% agarose gel in the presence of the pBR marker digested by HaeIII.

The chosen primers enable one to amplify a 420-bp fragment. Pab and Ppr enable one to obtain a 420-bp PCR product regardless of the quantity of template between 0.5 ng and 1 μg. A PCR product was also obtained under these same conditions in the presence of 10 pg of DNA template.

7) Amplification Capability of Pab and Ppr at High Temperatures

The tests of activity of the recombinant polymerases of Pyrococcus abyssi (Pab) and of Pyrococcus sp. GE 23 (Ppr) done using the method of incorporation of labeled dNTP demonstrated, under the buffer conditions used, a residual activity up to 85° C. Beyond this temperature, possible degradation of the substrate could mask the activity of the polymerases of the invention. It is of interest however to evaluate whether this ability can be taken advantage of for in vitro gene amplification, knowing that certain specific applications could proceed from this:

PCR using templates having blocking secondary structures at the usual elongation temperatures of 72 to 74° C.,

Direct reverse PCR using a double-stranded circular template (chromosome).

The principles of inverse PCR (iPCR) and of the new method worked out with Pab, called high-temperature inverse PCR (HT-iPCR) are represented in the diagrams of FIG. 14. A double strand of DNA, with a partially known sequence represented “in bold” in FIG. 14, is cut by a restriction enzyme [Eco]RI, diluted and ligated in order to form a double-stranded circular DNA molecule.

In conventional inverse PCR (procedure indicated as 1, 2 and 3 in FIG. 14), the circular molecules are linearized by RII and the amplification is done using the linearized DNA. In HT-iPCR, the amplification is done using the circular molecules (procedure indicated by 2′ in FIG. 14).

a) Materials and Methods

The DNA template used for these studies is a 2.2-kb circular DNA fragment. This fragment is obtained by digestion of the genomic DNA of the Thermococcus sp. GE 8 isolate by the enzyme Xho[I], purification using 0.8% agarose gel and elution of the 2 to 2.5-kb band by the GeneClean method, then ligation of the ends of the linear fragments by T4 ligase. The oligonucleotide primers are chosen from the known sequence region of this circularized fragment so as to copy from the known region towards the unknown sequence region (FIG. 14).

The amplification cycles were carried out with a [96-]wellthermocycler of the company Stratagene under the following conditions:

HT-iPCR with a single cycle at 85° C.:

94° C., 15 sec/1 cycle

94° C., 15 sec/56° C., 45 sec/85° C., 4 min/1 cycle

94° C., 15 sec/56° C., 45 sec/82-78° C., 4 min/1 cycle

94° C., 15 sec/56° C., 45 sec/76-72° C., 4 min/1 cycle

94° C., 15 sec/56° C., 45 sec/72° C., 4 min/27 cycles

HT-iPCR continuous at 85° C.:

94° C., 15 sec/1 cycle

94° C., 15 sec/56° C., 45 sec/85° C., 4 min/30 cycles storage at 4° C.

The results are visualized using 0.8% agarose gel.

FIG. 15 represents the comparison of the results of iPCR and HT-iPCR using Taq and Pab:

lane 1: “Raoul” marker (company Appligene-Oncor)

lane 2: HT-iPCR with Pab

lane 3: HT-iPCR with Taq

lane 4: i PCR with Taq.

FIG. 16 represents PCR at high temperature (elongation at 85° C. using 30 cycles):

lane 1: “Raoul” marker (company Appligene-Oncor)

lane 2: Pab

lane 3: Ppr

lane 4: control without DNA

lane 5: Vent.

b) Results

The results of inverse PCR with a single initial high temperature elongation cycle (85° C.) reveal an excellent behavior of Pab, and an inability of Taq (Perkin-Elmer) to perform this type of reaction. The control inverse PCR after linearization of the template by Taq provides a signal of low amplitude under the chosen conditions (FIG. 15).

The results obtained with 30 amplification cycles with elongation temperatures of 85° C. reveal an excellent ability of Pab to perform this type of reaction (FIG. 16). Ppr is also capable of amplifying the target DNA under these conditions, but Vent polymerase is incapable as is Pfu.

The results reported above make remarkable applications of the polymerases of the invention possible.

On one hand, the amplification is possible of DNA fragments which have secondary structures making elongation at temperatures of 72-74° C. difficult. The temperature rise up to 85° C. allows one to resolve these secondary structures which can form on single strands in the step of hybridization of the primers.

On the other hand, it is possible to use this on a chromosome when a small part of a sequence of a gene is known. The method disclosed above is generally applied as follows:

digestion of the genomic DNA by several restriction enzymes,

ligation by a ligase, such as T4 ligase, of the digestion products,

HT-iPCR using primers in the opposite direction on the known sequence region using Pab or Ppr,

possibly sequencing of the amplification products.

8) Study of the Thermostability of the Recombinant Enzymes of the Invention

a) Materials and Methods

In order to perform the tests necessary for this study, the DNA polymerases Pab and Ppr are diluted in a conditioning buffer (20 mM Tris HCl pH=8.0; 0.1 mM EDTA; 1 mM dithiothreitol; 50% glycerol; 0.5% Tween 20; 0.5% Nonidet 40; 0.2 mg/mL BSA), in such a way as to add 0.01 U of polymerase per test and to put oneself under nonsaturating conditions. Thus, 0.01 U of Pab or of Ppr are incubated in 20 μL of incubation buffer (10 mM Tris HCl pP=9.0; 50 mM KCl; 3 mM MgSO₄; 0.1% Tween) for different times (0 to 36 h), at 92° C., at 95° C. or at 100° C. The same number of test tubes as the number of different incubation times was prepared from the same initial mixture. The different tubes are incubated in a dry bath (PCR unit). At the end of incubation, the tubes are put in ice and the residual activity of the enzyme will be measured at 72° C. as described hereafter.

The activity test is performed in a final volume of 100 μL of incubation buffer (10 mM Tris HCl pP=9.0; 50 mM KCl; 3 mM MgSO₄; 0.1% Tween) under the following conditions:

13 μg of activated calf thymus DNA

500 μM of each of 4 dNTP

10 μCi of one of the four DNTP labeled with ³²P used as marker (dATP or dNTP were used)

20 μL of the solution corresponding to the test of inactivation by temperature.

The tests are incubated for 30 min at 70° C. 10 FL of each test are removed after 10 min, 20 min, and 30 min of incubation, and are then deposited on DE81 paper (Whatmann). Condensing before washing is then done dry by the Cerenkov method. The DE81 papers are then washed three times for 5 min in 0.5 mM solution of Na₂HPO₄ in order to eliminate the unincorporated DNTP. A passage with alcohol makes possible rapid drying of the papers which are counted again. A negative control (To) is done without DNA polymerase, and a positive control is done with DNA polymerase not temperature treated, corresponding to time 0 h. A polymerase unit is the quantity of enzyme necessary for the incorporation of 10 nmol of nucleosides in acid-soluble products in 30 min at 72° C. under the test conditions. The polymerase activity is calculated by taking the average of the total counts before washing in 10 μL of deposit. They correspond to 4×5 nmol of each dNTP, or 20 nmol of dNTP total. From each value after washing (Ci), it is necessary to subtract the value of the negative control To (without enzyme).

 Let, U/EL=(Ci—To)×(30 min/incubation time)×((100 μL/10 μL deposit)×(polymerase dilution)Ct for 10 nmol)×μL of polymerase added

b) Results.

The two enzymes were studied at three temperatures 92° C., 95° C. and 100° C. All the studies were done in parallel with the same substrates. The results are represented in the curves of FIGS. 17 to 20. For FIGS. 19 (Table V hereafter) and 20 (Table VI hereafter), the different polymerases studied are reduced to the same basis with regard to the initial activity, in order to facilitate the comparative study. A fourth temperature of 105° C. was also studied for Pab but is not illustrated in the figures.

FIG. 19: Pab activity

Table III below reports the results of the inactivation of the Pab as a function of time at 100° C., 95° C. and 92° C.

TABLE III Temps Inactivation at Inactivation at Inactivation at (hours) 100° C. 95° C. 92° C. 0 23,8 22.3 25 1 23,6 2 21,3 25,8 27,1 3 19,7 4 17,2 19,9 23,1 5 14,1 6 15,9 17,1 22,8 7 12,6 8 11,2 14,9 21,8 9 10 10,5 13,6 19,5 12 12,7 18 14 11,6 14,05 16 8,6 11,6 11,2 18 7,5 10,6 10,3 20 9,4 9,9 22 9,7 7,5 24 6,2 8 7 29 7,1 33 7 36 4,3 5,3 6,5 Key: 1 Time (h) 2 Inactivation at 100° C. 3 Inactivation at 95° C. 4 Inactivation at 92° C. FIG. 18: Ppr activity

Table IV below reports the results of the inactivation of the Ppr as a function of time at 100° C., 95° C. and 92° C.

TABLE IV Temps Inactivation at Inactivation at Inactivation at (hours) 100° C. 95° C. 92° C. 0 6,5 7,66 7,88 1 4,9 5,5 8,98 2 3,75 5,63 7,09 3 1,9 5,23 6,36 4 1 4,8 4,94 4,5 5,3 5 5,25 6 0 5,27 7 4,8 8 4,44 9 3,75 10 4,34 11 3,28 12 3,92 13 3,35 14 4,11 15 2,14 16 2,63 17 1,94 18 2,8 24 1,65 29 1,84 33 1,06 2,46 36 1,23 Key: 1 Time (h) 2 Inactivation at 100° C. 3 Inactivation at 95° C. 4 Inactivation at 92° C. FIG. 19: Pab and Ppr activity after inactivation at 100° C.

FIG. 19: Pab and Ppr activity after inactivation at 100° C.

Table V below reports the activity of Pab and Ppr after inactivation at 100° C.

TABLE V Temps (hour) Pab Ppr 0 23,8 23,8 1 23,6 17,9 2 21,3 13,7 3 19,7 6,9 4 17,2 3,7 5 14,1 6 15,9 0 7 12,6 8 11,2 10 10,5 16 8,6 18 7,5 24 6,2 29 7,1 33 7 36 4,3 Key: 1 Time (h) FIG. 20: Pab, Ppr, and Thermus aquaticus (Taq) polymerase activity after inactivation at 92° C.

Table VI below reports the activity of Pab, Ppr, and Taq after inactivation at 92° C.

TABLE VI Temps (hour) Pab Taq Ppr 0 25 27,7 25 1 26,5 28,5 2 27,1 22,5 22,5 3 20,2 20,2 4 23,1 19 15,6 5 15,7 16,6 6 22,8 14,5 16,7 7 15,2 8 21,8 12,3 14,1 10 19,5 13,7 12 18 12,5 14 14,05 13 16 11,2 8,3 18 10,3 8,9 20 9,9 22 7,5 24 2,3 5,2 29 5,8 36 6,5 0,5 3,9 48 0,8 56 2,2 72 1 84 0,7 Key: 1 Time (h)

The analysis of the curves of FIGS. 17 to 20 shows that:

Pab keeps 90% of its activity after a treatment of 5 hs at 92° C, 70% after 5 h at 95° C. and 60% after 5 h at 100° C. Pab keeps 50% of its activity after a treatment of 90 min at 105° C.

Ppr keeps 68% of its activity after 5 h at 92° C., 65% after 5 h at 95° C. and 10% after 5 h at 100° C.

In comparison, Taq polymerase keeps 55% of its activity after 5 h at 92° C., but it only has a half-life of 90 min at 95° C. and of 5 min at 100° C.

According to the curves of FIGS. 17 to 20 and the comments above, the enzyme Pab is more thermostable than Ppr in spite of a difference of only ten residues between their sequences. The enzyme Pab is the most thermostable currently described with a half-life at 95° C. of 18 h and more than 8 h at 100° C. The enzyme Ppr has a thermostability comparable with that published for Vent or even better with 2 h half-life at 100° C.

SEQUENCE LISTING <160> NUMBER OF SEQ ID NOS: 10 <210> SEQ ID NO 1 <211> LENGTH: 4446 <212> TYPE: DNA <213> ORGANISM: archaeboacteria pyroccocus <220> FEATURE: <221> NAME/KEY: CDS <222> LOCATION: (1547)..(3862) <221> NAME/KEY: stop codon <222> LOCATION: (3860)..(3862) <400> SEQUENCE: 1 cgaagatgag agatttggtg gaatgccgac ttacgggcaa gaaatttgag agagataaaa 60 tcaacgttaa gatagcggtg gcctattctg gaggaagcga tagctcagcc acagtaaaga 120 tactgagatg ggctggcttt gatgtggtcc caataacggc gaggcttccc cacataagca 180 aagaggagtt acgggaagaa actctattcg tggaagttcc tgggtacctt gaggagatgg 240 agaggttaat agaaaagagg gcccctatct gtggaaggtg ccactctatg gttatgagag 300 ctgttgcgag aaaaggttag ggagcttaaa ataagaatac tcgctactgg agacatgctc 360 agcataggaa gcgggtcaat ctacgagaaa gaaaatcttg tgattttgaa cttaccagct 420 ttcctatcac taaacaaggt tgaccttctg agcatactag gctgggagga ttatgagttt 480 aagtatggat gccccctttg gagggaggcc gtgaaaaggg ctccaataat gaagaggttt 540 gcaatccaga gggttctgag ggaattgagg gcaggggcaa taaacgagaa tattgctaag 600 aaacttattt ttgatatatt aagggcctaa acgaacctcg ccggtctgag ggttttcact 660 ttaatttcct tgtctatcgt aaccctgaac ccttccttgg ccacataggt tttcacgccg 720 gtaacgtttt ggatatactg ggcctcctta tagggaccag cgaagtgcat cttcatgccg 780 agatgcgtca tcacgagaac ttcaggcctt tgcttcattg cctttagcat gtaaactatg 840 tcgtcggttg ataagtggta gggaatcttc atgtccctgg gcctcgttac tgaggctatc 900 aaaactctcg acccatcatg ccagcttacc agctctggaa aatactcagt atccgctatg 960 tacgagatat ccccaaggct ggtttttaat ctaaagccta tcgttgttga gtcgctgtgc 1020 tgggatggag ttattatcat ctcctcattt cctaacctaa acctgtcccc aggattgggg 1080 gcatggactt cctctaatgc ctccaagtgg tacttgctca gggctggggt atgatcctcg 1140 cccccataaa acacgcttct agaacctatt agggttcccc tcttcttagt aacaccgtat 1200 gtcattccca caacgaacac ctcggcggcg gtggagtgat cggtgtgtct atgcgaaatg 1260 aagagaacat ctatcttcct ggggtctaac ttgtatctaa tcatcctaac tagcgctcca 1320 ggcccaggat ccacaaagat atttttgctt gccttgatga agaatccccc tgtggatctt 1380 acttgagtta tcgtcacgaa cctgccccca ccggcaccca agaacgtaat ctctatcatt 1440 tttagtcccg aaattaaagt gcgaggctta tgcttttaag gatgtatggc gaaaggtgaa 1500 gtttattaga agttagaatc taaagatttc agattgggtg ggggta atg ata atc 1555 Met Ile Ile 1 gat gct gat tac ata acg gaa gat ggc aag ccg ata ata aga ata ttc 1603 Asp Ala Asp Tyr Ile Thr Glu Asp Gly Lys Pro Ile Ile Arg Ile Phe 5 10 15 aaa aag gaa aag gga gag ttt aag gta gaa tac gat agg acg ttt aga 1651 Lys Lys Glu Lys Gly Glu Phe Lys Val Glu Tyr Asp Arg Thr Phe Arg 20 25 30 35 ccc tac att tac gct ctt tta aag gat gat tcg gcc ata gat gag gtt 1699 Pro Tyr Ile Tyr Ala Leu Leu Lys Asp Asp Ser Ala Ile Asp Glu Val 40 45 50 aag aag ata acc gcc gag agg cac gga aag ata gtc agg ata acc gaa 1747 Lys Lys Ile Thr Ala Glu Arg His Gly Lys Ile Val Arg Ile Thr Glu 55 60 65 gtt gag aaa gtc cag aag aaa ttc cta gga agg cca ata gaa gtc tgg 1795 Val Glu Lys Val Gln Lys Lys Phe Leu Gly Arg Pro Ile Glu Val Trp 70 75 80 aag ctg tac ctt gag cat cca caa gac gtt cca gct atc aga gag aag 1843 Lys Leu Tyr Leu Glu His Pro Gln Asp Val Pro Ala Ile Arg Glu Lys 85 90 95 ata agg gaa cat cca gct gta gtt gat ata ttc gaa tac gac ata ccc 1891 Ile Arg Glu His Pro Ala Val Val Asp Ile Phe Glu Tyr Asp Ile Pro 100 105 110 115 ttt gcg aaa cgc tac cta ata gat aag gga ttg act cca atg gag ggg 1939 Phe Ala Lys Arg Tyr Leu Ile Asp Lys Gly Leu Thr Pro Met Glu Gly 120 125 130 aac gag gag cta acg ttt cta gca gtt gac ata gaa aca ttg tac cat 1987 Asn Glu Glu Leu Thr Phe Leu Ala Val Asp Ile Glu Thr Leu Tyr His 135 140 145 gaa gga gag gag ttc ggg aaa ggc cct ata atc atg atc agc tac gcc 2035 Glu Gly Glu Glu Phe Gly Lys Gly Pro Ile Ile Met Ile Ser Tyr Ala 150 155 160 gac gag gaa ggg gcc aag gtg ata act tgg aag agc ata gac tta cct 2083 Asp Glu Glu Gly Ala Lys Val Ile Thr Trp Lys Ser Ile Asp Leu Pro 165 170 175 tac gtt gaa gtg gtt tca agc gag agg gag atg ata aag agg ctc gtg 2131 Tyr Val Glu Val Val Ser Ser Glu Arg Glu Met Ile Lys Arg Leu Val 180 185 190 195 aag gta att aga gag aag gat ccc gac gtg ata ata acg tac aat ggt 2179 Lys Val Ile Arg Glu Lys Asp Pro Asp Val Ile Ile Thr Tyr Asn Gly 200 205 210 gat aat ttc gac ttt ccg tac ctc tta aag agg gct gaa aag ctc gga 2227 Asp Asn Phe Asp Phe Pro Tyr Leu Leu Lys Arg Ala Glu Lys Leu Gly 215 220 225 ata aag ctc ccc ctt gga agg gac aat agc gag ccg aag atg cag agg 2275 Ile Lys Leu Pro Leu Gly Arg Asp Asn Ser Glu Pro Lys Met Gln Arg 230 235 240 atg ggg gat tca tta gct gta gag ata aag ggc aga ata cac ttc gat 2323 Met Gly Asp Ser Leu Ala Val Glu Ile Lys Gly Arg Ile His Phe Asp 245 250 255 tta ttc ccc gtc ata aga aga acg atc aac ctt cca aca tac acc ctc 2371 Leu Phe Pro Val Ile Arg Arg Thr Ile Asn Leu Pro Thr Tyr Thr Leu 260 265 270 275 gaa gcg gtt tat gag gct ata ttt gga aag tct aag gag aaa gtc tat 2419 Glu Ala Val Tyr Glu Ala Ile Phe Gly Lys Ser Lys Glu Lys Val Tyr 280 285 290 gcc cat gag ata gct gag gcc tgg gaa acc ggg aaa ggg cta gag agg 2467 Ala His Glu Ile Ala Glu Ala Trp Glu Thr Gly Lys Gly Leu Glu Arg 295 300 305 gta gct aag tat tca atg gaa gat gcg aag gta acc ttt gag ctc gga 2515 Val Ala Lys Tyr Ser Met Glu Asp Ala Lys Val Thr Phe Glu Leu Gly 310 315 320 aag gag ttc ttc cca atg gaa gcc cag cta gct agg ctc gtt ggc cag 2563 Lys Glu Phe Phe Pro Met Glu Ala Gln Leu Ala Arg Leu Val Gly Gln 325 330 335 cca gtt tgg gac gtt tca agg tcg agc acc gga aac ctc gtt gag tgg 2611 Pro Val Trp Asp Val Ser Arg Ser Ser Thr Gly Asn Leu Val Glu Trp 340 345 350 355 ttt ctc ctt agg aag gcc tac gag aga aat gag ctc gcg ccc aat aaa 2659 Phe Leu Leu Arg Lys Ala Tyr Glu Arg Asn Glu Leu Ala Pro Asn Lys 360 365 370 ccg gac gag agg gaa tac gag aga agg cta aga gag agc tat gaa ggg 2707 Pro Asp Glu Arg Glu Tyr Glu Arg Arg Leu Arg Glu Ser Tyr Glu Gly 375 380 385 ggt tac gtt aag gag cca gag aag gga ttg tgg gaa ggg ata gtc agc 2755 Gly Tyr Val Lys Glu Pro Glu Lys Gly Leu Trp Glu Gly Ile Val Ser 390 395 400 tta gac ttt agg tcc cta tat ccg tct ata att ata act cac aac gtc 2803 Leu Asp Phe Arg Ser Leu Tyr Pro Ser Ile Ile Ile Thr His Asn Val 405 410 415 tca cca gac act ttg aat aga gaa aat tgc aag gaa tac gac gtt gcc 2851 Ser Pro Asp Thr Leu Asn Arg Glu Asn Cys Lys Glu Tyr Asp Val Ala 420 425 430 435 ccc caa gtg ggg cac aga ttc tgc aag gat ttc cca gga ttc ata cca 2899 Pro Gln Val Gly His Arg Phe Cys Lys Asp Phe Pro Gly Phe Ile Pro 440 445 450 agc tta ctg ggt aac tta ctg gag gag aga caa aag ata aaa aag aga 2947 Ser Leu Leu Gly Asn Leu Leu Glu Glu Arg Gln Lys Ile Lys Lys Arg 455 460 465 atg aaa gaa agt aaa gat ccc gtc gag aag aaa ctc ctt gat tac aga 2995 Met Lys Glu Ser Lys Asp Pro Val Glu Lys Lys Leu Leu Asp Tyr Arg 470 475 480 cag aga gct ata aaa ata ctt gca aac agc tat tat ggc tat tat gga 3043 Gln Arg Ala Ile Lys Ile Leu Ala Asn Ser Tyr Tyr Gly Tyr Tyr Gly 485 490 495 tat gca aag gcc aga tgg tac tgt aag gag tgt gca gag agc gta act 3091 Tyr Ala Lys Ala Arg Trp Tyr Cys Lys Glu Cys Ala Glu Ser Val Thr 500 505 510 515 gca tgg ggg agg caa tac ata gat cta gtt aga aga gag ctt gaa agc 3139 Ala Trp Gly Arg Gln Tyr Ile Asp Leu Val Arg Arg Glu Leu Glu Ser 520 525 530 agc gga ttc aag gtt ctg tac ata gac act gat ggc ctc tac gcg acc 3187 Ser Gly Phe Lys Val Leu Tyr Ile Asp Thr Asp Gly Leu Tyr Ala Thr 535 540 545 att cct ggg gcc aag cca aat gag ata aaa gaa aag gcc ctt aag ttc 3235 Ile Pro Gly Ala Lys Pro Asn Glu Ile Lys Glu Lys Ala Leu Lys Phe 550 555 560 gtc gag tac ata aac tcc aag tta cct ggg ctt ctt gaa ttg gaa tac 3283 Val Glu Tyr Ile Asn Ser Lys Leu Pro Gly Leu Leu Glu Leu Glu Tyr 565 570 575 gaa ggt ttc tac gcg aga ggg ttc ttc gtg acg aag aaa aag tac gca 3331 Glu Gly Phe Tyr Ala Arg Gly Phe Phe Val Thr Lys Lys Lys Tyr Ala 580 585 590 595 cta atc gac gag gaa gga aag ata gtt acg agg ggg ctc gaa ata gta 3379 Leu Ile Asp Glu Glu Gly Lys Ile Val Thr Arg Gly Leu Glu Ile Val 600 605 610 agg aga gat tgg agt gaa ata gca aag gag acc caa gct aag gtt ctc 3427 Arg Arg Asp Trp Ser Glu Ile Ala Lys Glu Thr Gln Ala Lys Val Leu 615 620 625 gag gca ata ctc aag cac ggt aac gtt gat gag gcc gta aaa ata gta 3475 Glu Ala Ile Leu Lys His Gly Asn Val Asp Glu Ala Val Lys Ile Val 630 635 640 aag gag gtt aca gaa aaa ctc agt aaa tat gaa ata cca ccc gaa aag 3523 Lys Glu Val Thr Glu Lys Leu Ser Lys Tyr Glu Ile Pro Pro Glu Lys 645 650 655 ctt gta att tat gag cag ata acg agg cct ctg agc gag tat aaa gcg 3571 Leu Val Ile Tyr Glu Gln Ile Thr Arg Pro Leu Ser Glu Tyr Lys Ala 660 665 670 675 ata ggc cct cac gtt gca gta gct aaa agg ctc gca gcg aag gga gta 3619 Ile Gly Pro His Val Ala Val Ala Lys Arg Leu Ala Ala Lys Gly Val 680 685 690 aaa gtt aag cca ggg atg gtt atc ggt tac ata gtt ttg agg gga gac 3667 Lys Val Lys Pro Gly Met Val Ile Gly Tyr Ile Val Leu Arg Gly Asp 695 700 705 ggg cca ata agc aag agg gcc ata gct ata gag gag ttc gat ccc aaa 3715 Gly Pro Ile Ser Lys Arg Ala Ile Ala Ile Glu Glu Phe Asp Pro Lys 710 715 720 aag cat aag tac gat gcc gaa tac tac ata gag aac caa gtt ctg cca 3763 Lys His Lys Tyr Asp Ala Glu Tyr Tyr Ile Glu Asn Gln Val Leu Pro 725 730 735 gcg gtg gag agg ata ttg aga gca ttt ggt tat cgc aaa gaa gat ttg 3811 Ala Val Glu Arg Ile Leu Arg Ala Phe Gly Tyr Arg Lys Glu Asp Leu 740 745 750 755 agg tat caa aaa act aaa caa gtg ggc ctc gga gca tgg ctt aag ttc 3859 Arg Tyr Gln Lys Thr Lys Gln Val Gly Leu Gly Ala Trp Leu Lys Phe 760 765 770 tag ctacccagat gtcaccgtat ctcaacaggt attcctggag atctcttaaa 3912 tcaactacaa gctcttcctc aagttccata aagtttattg actttatcgg tttaattatg 3972 agcttatagg agcctagaac cccagaaatc ttaactctaa agactcttga agctagctct 4032 atcagttcaa gaactatgtc cttcttaagg aacgaggaat taatgaaaac tattccttta 4092 ccgttcggat cctggagagc cattttccca actaatgtga agaagagttc gctttcaatg 4152 tagttactct cccttgtttt tagaagtctc tctaagccga cgtttatagt gaaccgtctt 4212 ttccccgtgc ttctcaaggg tagtgaaaag ttgttttctc caaactccga tatccgagcc 4272 tatttctatt ctcttcacta cgctgcccgt ttttataaat ccaccaagtt taacgaccct 4332 ggcactatct ataacatcgg tcttcagacc caatagcctt aaggtggttt ctcaaaactg 4392 agaccttccc tttagagcat tcaagaccat tagaagatca ggtctattgg ctcg 4446 <210> SEQ ID NO 2 <211> LENGTH: 771 <212> TYPE: PRT <213> ORGANISM: archaeboacteria pyroccocus <400> SEQUENCE: 2 Met Ile Ile Asp Ala Asp Tyr Ile Thr Glu Asp Gly Lys Pro Ile Ile 1 5 10 15 Arg Ile Phe Lys Lys Glu Lys Gly Glu Phe Lys Val Glu Tyr Asp Arg 20 25 30 Thr Phe Arg Pro Tyr Ile Tyr Ala Leu Leu Lys Asp Asp Ser Ala Ile 35 40 45 Asp Glu Val Lys Lys Ile Thr Ala Glu Arg His Gly Lys Ile Val Arg 50 55 60 Ile Thr Glu Val Glu Lys Val Gln Lys Lys Phe Leu Gly Arg Pro Ile 65 70 75 80 Glu Val Trp Lys Leu Tyr Leu Glu His Pro Gln Asp Val Pro Ala Ile 85 90 95 Arg Glu Lys Ile Arg Glu His Pro Ala Val Val Asp Ile Phe Glu Tyr 100 105 110 Asp Ile Pro Phe Ala Lys Arg Tyr Leu Ile Asp Lys Gly Leu Thr Pro 115 120 125 Met Glu Gly Asn Glu Glu Leu Thr Phe Leu Ala Val Asp Ile Glu Thr 130 135 140 Leu Tyr His Glu Gly Glu Glu Phe Gly Lys Gly Pro Ile Ile Met Ile 145 150 155 160 Ser Tyr Ala Asp Glu Glu Gly Ala Lys Val Ile Thr Trp Lys Ser Ile 165 170 175 Asp Leu Pro Tyr Val Glu Val Val Ser Ser Glu Arg Glu Met Ile Lys 180 185 190 Arg Leu Val Lys Val Ile Arg Glu Lys Asp Pro Asp Val Ile Ile Thr 195 200 205 Tyr Asn Gly Asp Asn Phe Asp Phe Pro Tyr Leu Leu Lys Arg Ala Glu 210 215 220 Lys Leu Gly Ile Lys Leu Pro Leu Gly Arg Asp Asn Ser Glu Pro Lys 225 230 235 240 Met Gln Arg Met Gly Asp Ser Leu Ala Val Glu Ile Lys Gly Arg Ile 245 250 255 His Phe Asp Leu Phe Pro Val Ile Arg Arg Thr Ile Asn Leu Pro Thr 260 265 270 Tyr Thr Leu Glu Ala Val Tyr Glu Ala Ile Phe Gly Lys Ser Lys Glu 275 280 285 Lys Val Tyr Ala His Glu Ile Ala Glu Ala Trp Glu Thr Gly Lys Gly 290 295 300 Leu Glu Arg Val Ala Lys Tyr Ser Met Glu Asp Ala Lys Val Thr Phe 305 310 315 320 Glu Leu Gly Lys Glu Phe Phe Pro Met Glu Ala Gln Leu Ala Arg Leu 325 330 335 Val Gly Gln Pro Val Trp Asp Val Ser Arg Ser Ser Thr Gly Asn Leu 340 345 350 Val Glu Trp Phe Leu Leu Arg Lys Ala Tyr Glu Arg Asn Glu Leu Ala 355 360 365 Pro Asn Lys Pro Asp Glu Arg Glu Tyr Glu Arg Arg Leu Arg Glu Ser 370 375 380 Tyr Glu Gly Gly Tyr Val Lys Glu Pro Glu Lys Gly Leu Trp Glu Gly 385 390 395 400 Ile Val Ser Leu Asp Phe Arg Ser Leu Tyr Pro Ser Ile Ile Ile Thr 405 410 415 His Asn Val Ser Pro Asp Thr Leu Asn Arg Glu Asn Cys Lys Glu Tyr 420 425 430 Asp Val Ala Pro Gln Val Gly His Arg Phe Cys Lys Asp Phe Pro Gly 435 440 445 Phe Ile Pro Ser Leu Leu Gly Asn Leu Leu Glu Glu Arg Gln Lys Ile 450 455 460 Lys Lys Arg Met Lys Glu Ser Lys Asp Pro Val Glu Lys Lys Leu Leu 465 470 475 480 Asp Tyr Arg Gln Arg Ala Ile Lys Ile Leu Ala Asn Ser Tyr Tyr Gly 485 490 495 Tyr Tyr Gly Tyr Ala Lys Ala Arg Trp Tyr Cys Lys Glu Cys Ala Glu 500 505 510 Ser Val Thr Ala Trp Gly Arg Gln Tyr Ile Asp Leu Val Arg Arg Glu 515 520 525 Leu Glu Ser Ser Gly Phe Lys Val Leu Tyr Ile Asp Thr Asp Gly Leu 530 535 540 Tyr Ala Thr Ile Pro Gly Ala Lys Pro Asn Glu Ile Lys Glu Lys Ala 545 550 555 560 Leu Lys Phe Val Glu Tyr Ile Asn Ser Lys Leu Pro Gly Leu Leu Glu 565 570 575 Leu Glu Tyr Glu Gly Phe Tyr Ala Arg Gly Phe Phe Val Thr Lys Lys 580 585 590 Lys Tyr Ala Leu Ile Asp Glu Glu Gly Lys Ile Val Thr Arg Gly Leu 595 600 605 Glu Ile Val Arg Arg Asp Trp Ser Glu Ile Ala Lys Glu Thr Gln Ala 610 615 620 Lys Val Leu Glu Ala Ile Leu Lys His Gly Asn Val Asp Glu Ala Val 625 630 635 640 Lys Ile Val Lys Glu Val Thr Glu Lys Leu Ser Lys Tyr Glu Ile Pro 645 650 655 Pro Glu Lys Leu Val Ile Tyr Glu Gln Ile Thr Arg Pro Leu Ser Glu 660 665 670 Tyr Lys Ala Ile Gly Pro His Val Ala Val Ala Lys Arg Leu Ala Ala 675 680 685 Lys Gly Val Lys Val Lys Pro Gly Met Val Ile Gly Tyr Ile Val Leu 690 695 700 Arg Gly Asp Gly Pro Ile Ser Lys Arg Ala Ile Ala Ile Glu Glu Phe 705 710 715 720 Asp Pro Lys Lys His Lys Tyr Asp Ala Glu Tyr Tyr Ile Glu Asn Gln 725 730 735 Val Leu Pro Ala Val Glu Arg Ile Leu Arg Ala Phe Gly Tyr Arg Lys 740 745 750 Glu Asp Leu Arg Tyr Gln Lys Thr Lys Gln Val Gly Leu Gly Ala Trp 755 760 765 Leu Lys Phe 770 <210> SEQ ID NO 3 <211> LENGTH: 2995 <212> TYPE: DNA <213> ORGANISM: archaeobacteria Pyroccocus GE 5 <220> FEATURE: <221> NAME/KEY: CDS <222> LOCATION: (679)..(2991) <221> NAME/KEY: misc_feature <222> LOCATION: (46)..(46) <223> OTHER INFORMATION: n is uncertain nucleotide <221> NAME/KEY: stop codon <222> LOCATION: (2992)..(2994) <400> SEQUENCE: 3 tcatgtcctg gggcttggtt acggaggcta tcaaaatatt ggaccnttcg tgccagctta 60 ccagctctgg aaaatactca gtatccgcta tgtacgagat atccccaagg ctagttttta 120 atctaaagcc tatagttgtt gggtcgctgt gctgggatgg agttattatc atctcctcat 180 ttcctagcct aaacctgtcc ccaggattag gagcatggac ttcctctaat gcctccaagt 240 ggtacttgct cagggctggg gtatgatcct cgtccccata aaccacgctt ctagaaccta 300 ttagggttcc cctcttctta gtwaccccat aggtcatccc ytcaacgatc acytcggcat 360 cgttgcagtg atcggtgtgt ctatgcgaga tgaagagaac atctatcttc ctggggtcta 420 gcttatatct aatcatccta actagcgctc caggcccagg gtccacaaag atatttttgc 480 ttgccttgat gaagaatcca cccgtagatc ttacttgagt tatcgtcacg aacctgcccc 540 caccggcacc caggaacgta atctctatca tttttagtcc cgaaattaaa gtgcgaggct 600 tatgctttta aggatgtatg gcgaaaggtg aagtttatta gaagttagaa tctaaagatt 660 tcagattggg tgggggta atg ata atc gat gct gat tac ata acg gaa gat 711 Met Ile Ile Asp Ala Asp Tyr Ile Thr Glu Asp 1 5 10 ggc aag ccg ata ata agg ata ttc aaa aag gaa aag gga gag ttt aag 759 Gly Lys Pro Ile Ile Arg Ile Phe Lys Lys Glu Lys Gly Glu Phe Lys 15 20 25 gta gaa tac gat agg acg ttt aga ccc tac att tat gct ctt tta aag 807 Val Glu Tyr Asp Arg Thr Phe Arg Pro Tyr Ile Tyr Ala Leu Leu Lys 30 35 40 gat gat tcg gcc ata gat gag gtt aag aag ata acc gcc gag agg cac 855 Asp Asp Ser Ala Ile Asp Glu Val Lys Lys Ile Thr Ala Glu Arg His 45 50 55 gga aag ata gtc agg ata acc gag gtt gag aaa gtc cag aag aaa ttc 903 Gly Lys Ile Val Arg Ile Thr Glu Val Glu Lys Val Gln Lys Lys Phe 60 65 70 75 cta gga agg cca ata gaa gtc tgg aag ctc tat ctt gag cat ccc cag 951 Leu Gly Arg Pro Ile Glu Val Trp Lys Leu Tyr Leu Glu His Pro Gln 80 85 90 gat gtt cca gcc ata aga gag aag ata agg gaa cat cca gct gta gtt 999 Asp Val Pro Ala Ile Arg Glu Lys Ile Arg Glu His Pro Ala Val Val 95 100 105 gat ata ttt gaa tac gac ata ccc ttt gcg aag cgc tac ctc ata gac 1047 Asp Ile Phe Glu Tyr Asp Ile Pro Phe Ala Lys Arg Tyr Leu Ile Asp 110 115 120 aag gga ttg act cca atg gag ggg aac gag gag cta acg ttt cta gcc 1095 Lys Gly Leu Thr Pro Met Glu Gly Asn Glu Glu Leu Thr Phe Leu Ala 125 130 135 gtt gat ata gaa aca ttg tac cat gaa gga gag gag ttc ggg aaa ggg 1143 Val Asp Ile Glu Thr Leu Tyr His Glu Gly Glu Glu Phe Gly Lys Gly 140 145 150 155 cca ata ata atg atc agc tac gcc gac gag gaa ggg gcc aag gtg ata 1191 Pro Ile Ile Met Ile Ser Tyr Ala Asp Glu Glu Gly Ala Lys Val Ile 160 165 170 act tgg aag agc ata gac tta cct tac gtt gaa gtg gtt tcg agc gag 1239 Thr Trp Lys Ser Ile Asp Leu Pro Tyr Val Glu Val Val Ser Ser Glu 175 180 185 agg gag atg ata aag agg ctc gtg aag gta att aga gag aaa gat ccc 1287 Arg Glu Met Ile Lys Arg Leu Val Lys Val Ile Arg Glu Lys Asp Pro 190 195 200 gac gtg ata ata acg tac aat ggt gat aat ttc gac ttt ccg tac ctc 1335 Asp Val Ile Ile Thr Tyr Asn Gly Asp Asn Phe Asp Phe Pro Tyr Leu 205 210 215 tta aag agg gct gaa aag ctc gga ata aag ctc ccc ctt gga agg gac 1383 Leu Lys Arg Ala Glu Lys Leu Gly Ile Lys Leu Pro Leu Gly Arg Asp 220 225 230 235 aat agc gag ccg aaa atg cag agg atg ggg gat tca tta gcc gta gag 1431 Asn Ser Glu Pro Lys Met Gln Arg Met Gly Asp Ser Leu Ala Val Glu 240 245 250 ata aag ggc aga ata cac ttc gat tta ttc ccc gcc ata aga aga acg 1479 Ile Lys Gly Arg Ile His Phe Asp Leu Phe Pro Ala Ile Arg Arg Thr 255 260 265 atc aac ctt cca aca tac acc ctc gaa acg gtt tat gag gtt ata ttt 1527 Ile Asn Leu Pro Thr Tyr Thr Leu Glu Thr Val Tyr Glu Val Ile Phe 270 275 280 gga aag tct aag gag aaa gtc tat gcc cat gag ata gct gag gcc tgg 1575 Gly Lys Ser Lys Glu Lys Val Tyr Ala His Glu Ile Ala Glu Ala Trp 285 290 295 gaa acc ggg aaa ggg cta gag agg gta gct aag tat tca atg gaa gat 1623 Glu Thr Gly Lys Gly Leu Glu Arg Val Ala Lys Tyr Ser Met Glu Asp 300 305 310 315 gcg aag gta acc tct gag ctc gga aag gag ttc ttc ccg atg gaa gcc 1671 Ala Lys Val Thr Ser Glu Leu Gly Lys Glu Phe Phe Pro Met Glu Ala 320 325 330 cag cta gct agg ctc gtt ggc cat cca gtt tgg gac gtt tca agg tcg 1719 Gln Leu Ala Arg Leu Val Gly His Pro Val Trp Asp Val Ser Arg Ser 335 340 345 agc acc gga aac ctc gtt gag tgg ttt ctc ctt acg aag gcc tac gag 1767 Ser Thr Gly Asn Leu Val Glu Trp Phe Leu Leu Thr Lys Ala Tyr Glu 350 355 360 aga aat gag ctc gcg ccc aat aaa ccg gac gag agg gaa tac gag aga 1815 Arg Asn Glu Leu Ala Pro Asn Lys Pro Asp Glu Arg Glu Tyr Glu Arg 365 370 375 agg cta aga gag agc tat gaa ggg ggt tac gtt aac gag cca gag aag 1863 Arg Leu Arg Glu Ser Tyr Glu Gly Gly Tyr Val Asn Glu Pro Glu Lys 380 385 390 395 gga ttg tgg gaa ggg ata gtc agc tta gac ttt agg tcc cta tat ccc 1911 Gly Leu Trp Glu Gly Ile Val Ser Leu Asp Phe Arg Ser Leu Tyr Pro 400 405 410 tct ata att ata act cac aac gtc tca cca gac act ttg aat aga gaa 1959 Ser Ile Ile Ile Thr His Asn Val Ser Pro Asp Thr Leu Asn Arg Glu 415 420 425 aat tgc aag gaa tat gac gtt gcc ccc caa gtg ggg cac aga ttc tgc 2007 Asn Cys Lys Glu Tyr Asp Val Ala Pro Gln Val Gly His Arg Phe Cys 430 435 440 aag gat ttc cca gga ttc ata cca agc tta ctg ggt aac cta ctg gag 2055 Lys Asp Phe Pro Gly Phe Ile Pro Ser Leu Leu Gly Asn Leu Leu Glu 445 450 455 gag aga caa aag ata aaa aag agg atg aaa gaa agt aaa gat ccc gtc 2103 Glu Arg Gln Lys Ile Lys Lys Arg Met Lys Glu Ser Lys Asp Pro Val 460 465 470 475 gag aag aaa ctc ctt gat tac aga cag aga gct ata aaa ata ctt gca 2151 Glu Lys Lys Leu Leu Asp Tyr Arg Gln Arg Ala Ile Lys Ile Leu Ala 480 485 490 aac agc tat tat ggc tat tat gga tat gca aag gcc aga tgg tac tgt 2199 Asn Ser Tyr Tyr Gly Tyr Tyr Gly Tyr Ala Lys Ala Arg Trp Tyr Cys 495 500 505 aaa gag tgt gca gag agc gta acc gca tgg gga agg cag tac ata gac 2247 Lys Glu Cys Ala Glu Ser Val Thr Ala Trp Gly Arg Gln Tyr Ile Asp 510 515 520 ctg gtt agg agg gaa ctt gag agc aga gga ttt aaa gtt ctc tac ata 2295 Leu Val Arg Arg Glu Leu Glu Ser Arg Gly Phe Lys Val Leu Tyr Ile 525 530 535 gac aca gat ggc ctc tac gca acg att cct gga gcc aag cat gag gaa 2343 Asp Thr Asp Gly Leu Tyr Ala Thr Ile Pro Gly Ala Lys His Glu Glu 540 545 550 555 ata aaa gag aag gca ttg aag ttc gtc gag tac ata aac tcc aag tta 2391 Ile Lys Glu Lys Ala Leu Lys Phe Val Glu Tyr Ile Asn Ser Lys Leu 560 565 570 cct ggg ctt ctt gaa ttg gaa tac gaa ggt ttc tac gcg aga ggg ttc 2439 Pro Gly Leu Leu Glu Leu Glu Tyr Glu Gly Phe Tyr Ala Arg Gly Phe 575 580 585 ttc gtg acg aag aaa aag tac gca cta atc gac gag gaa gga aag ata 2487 Phe Val Thr Lys Lys Lys Tyr Ala Leu Ile Asp Glu Glu Gly Lys Ile 590 595 600 gtt acg agg ggg ctc gaa ata gta agg aga gat tgg agt gaa ata gca 2535 Val Thr Arg Gly Leu Glu Ile Val Arg Arg Asp Trp Ser Glu Ile Ala 605 610 615 aag gag acc cag gcc aag gtt ctc gag gca ata ctc aag cac ggt aac 2583 Lys Glu Thr Gln Ala Lys Val Leu Glu Ala Ile Leu Lys His Gly Asn 620 625 630 635 gtt gat gag gcc gta aaa ata gta aag gag gtt aca gaa aaa ctc agt 2631 Val Asp Glu Ala Val Lys Ile Val Lys Glu Val Thr Glu Lys Leu Ser 640 645 650 aaa tat gaa ata cca ccc gaa aag ctt gta att tat gag cag ata acg 2679 Lys Tyr Glu Ile Pro Pro Glu Lys Leu Val Ile Tyr Glu Gln Ile Thr 655 660 665 agg cct ctg agc gag tat aaa gcg ata ggc cct cac gtt gca gta gct 2727 Arg Pro Leu Ser Glu Tyr Lys Ala Ile Gly Pro His Val Ala Val Ala 670 675 680 aaa agg ctc gca gcg aag gga gta aaa gtt aag cca ggg atg gtt atc 2775 Lys Arg Leu Ala Ala Lys Gly Val Lys Val Lys Pro Gly Met Val Ile 685 690 695 ggt tac ata gtt ttg agg gga gac ggg cca ata agc aag agg gcc ata 2823 Gly Tyr Ile Val Leu Arg Gly Asp Gly Pro Ile Ser Lys Arg Ala Ile 700 705 710 715 gct ata gag gag ttc gat ccc aaa aag cat aag tac gat gcc gaa tac 2871 Ala Ile Glu Glu Phe Asp Pro Lys Lys His Lys Tyr Asp Ala Glu Tyr 720 725 730 tac ata gag aac caa gtt ctg cca gcg gtg gag agg ata ttg aga gca 2919 Tyr Ile Glu Asn Gln Val Leu Pro Ala Val Glu Arg Ile Leu Arg Ala 735 740 745 ttt ggt tat cgc aaa gaa gat ttg agg tat caa aaa act aaa caa gtg 2967 Phe Gly Tyr Arg Lys Glu Asp Leu Arg Tyr Gln Lys Thr Lys Gln Val 750 755 760 ggc ctc gga gca tgg ctt aag ttc taga 2995 Gly Leu Gly Ala Trp Leu Lys Phe 765 770 <210> SEQ ID NO 4 <211> LENGTH: 771 <212> TYPE: PRT <213> ORGANISM: archaeobacteria Pyroccocus GE 5 <220> FEATURE: <400> SEQUENCE: 4 Met Ile Ile Asp Ala Asp Tyr Ile Thr Glu Asp Gly Lys Pro Ile Ile 1 5 10 15 Arg Ile Phe Lys Lys Glu Lys Gly Glu Phe Lys Val Glu Tyr Asp Arg 20 25 30 Thr Phe Arg Pro Tyr Ile Tyr Ala Leu Leu Lys Asp Asp Ser Ala Ile 35 40 45 Asp Glu Val Lys Lys Ile Thr Ala Glu Arg His Gly Lys Ile Val Arg 50 55 60 Ile Thr Glu Val Glu Lys Val Gln Lys Lys Phe Leu Gly Arg Pro Ile 65 70 75 80 Glu Val Trp Lys Leu Tyr Leu Glu His Pro Gln Asp Val Pro Ala Ile 85 90 95 Arg Glu Lys Ile Arg Glu His Pro Ala Val Val Asp Ile Phe Glu Tyr 100 105 110 Asp Ile Pro Phe Ala Lys Arg Tyr Leu Ile Asp Lys Gly Leu Thr Pro 115 120 125 Met Glu Gly Asn Glu Glu Leu Thr Phe Leu Ala Val Asp Ile Glu Thr 130 135 140 Leu Tyr His Glu Gly Glu Glu Phe Gly Lys Gly Pro Ile Ile Met Ile 145 150 155 160 Ser Tyr Ala Asp Glu Glu Gly Ala Lys Val Ile Thr Trp Lys Ser Ile 165 170 175 Asp Leu Pro Tyr Val Glu Val Val Ser Ser Glu Arg Glu Met Ile Lys 180 185 190 Arg Leu Val Lys Val Ile Arg Glu Lys Asp Pro Asp Val Ile Ile Thr 195 200 205 Tyr Asn Gly Asp Asn Phe Asp Phe Pro Tyr Leu Leu Lys Arg Ala Glu 210 215 220 Lys Leu Gly Ile Lys Leu Pro Leu Gly Arg Asp Asn Ser Glu Pro Lys 225 230 235 240 Met Gln Arg Met Gly Asp Ser Leu Ala Val Glu Ile Lys Gly Arg Ile 245 250 255 His Phe Asp Leu Phe Pro Ala Ile Arg Arg Thr Ile Asn Leu Pro Thr 260 265 270 Tyr Thr Leu Glu Thr Val Tyr Glu Val Ile Phe Gly Lys Ser Lys Glu 275 280 285 Lys Val Tyr Ala His Glu Ile Ala Glu Ala Trp Glu Thr Gly Lys Gly 290 295 300 Leu Glu Arg Val Ala Lys Tyr Ser Met Glu Asp Ala Lys Val Thr Ser 305 310 315 320 Glu Leu Gly Lys Glu Phe Phe Pro Met Glu Ala Gln Leu Ala Arg Leu 325 330 335 Val Gly His Pro Val Trp Asp Val Ser Arg Ser Ser Thr Gly Asn Leu 340 345 350 Val Glu Trp Phe Leu Leu Thr Lys Ala Tyr Glu Arg Asn Glu Leu Ala 355 360 365 Pro Asn Lys Pro Asp Glu Arg Glu Tyr Glu Arg Arg Leu Arg Glu Ser 370 375 380 Tyr Glu Gly Gly Tyr Val Asn Glu Pro Glu Lys Gly Leu Trp Glu Gly 385 390 395 400 Ile Val Ser Leu Asp Phe Arg Ser Leu Tyr Pro Ser Ile Ile Ile Thr 405 410 415 His Asn Val Ser Pro Asp Thr Leu Asn Arg Glu Asn Cys Lys Glu Tyr 420 425 430 Asp Val Ala Pro Gln Val Gly His Arg Phe Cys Lys Asp Phe Pro Gly 435 440 445 Phe Ile Pro Ser Leu Leu Gly Asn Leu Leu Glu Glu Arg Gln Lys Ile 450 455 460 Lys Lys Arg Met Lys Glu Ser Lys Asp Pro Val Glu Lys Lys Leu Leu 465 470 475 480 Asp Tyr Arg Gln Arg Ala Ile Lys Ile Leu Ala Asn Ser Tyr Tyr Gly 485 490 495 Tyr Tyr Gly Tyr Ala Lys Ala Arg Trp Tyr Cys Lys Glu Cys Ala Glu 500 505 510 Ser Val Thr Ala Trp Gly Arg Gln Tyr Ile Asp Leu Val Arg Arg Glu 515 520 525 Leu Glu Ser Arg Gly Phe Lys Val Leu Tyr Ile Asp Thr Asp Gly Leu 530 535 540 Tyr Ala Thr Ile Pro Gly Ala Lys His Glu Glu Ile Lys Glu Lys Ala 545 550 555 560 Leu Lys Phe Val Glu Tyr Ile Asn Ser Lys Leu Pro Gly Leu Leu Glu 565 570 575 Leu Glu Tyr Glu Gly Phe Tyr Ala Arg Gly Phe Phe Val Thr Lys Lys 580 585 590 Lys Tyr Ala Leu Ile Asp Glu Glu Gly Lys Ile Val Thr Arg Gly Leu 595 600 605 Glu Ile Val Arg Arg Asp Trp Ser Glu Ile Ala Lys Glu Thr Gln Ala 610 615 620 Lys Val Leu Glu Ala Ile Leu Lys His Gly Asn Val Asp Glu Ala Val 625 630 635 640 Lys Ile Val Lys Glu Val Thr Glu Lys Leu Ser Lys Tyr Glu Ile Pro 645 650 655 Pro Glu Lys Leu Val Ile Tyr Glu Gln Ile Thr Arg Pro Leu Ser Glu 660 665 670 Tyr Lys Ala Ile Gly Pro His Val Ala Val Ala Lys Arg Leu Ala Ala 675 680 685 Lys Gly Val Lys Val Lys Pro Gly Met Val Ile Gly Tyr Ile Val Leu 690 695 700 Arg Gly Asp Gly Pro Ile Ser Lys Arg Ala Ile Ala Ile Glu Glu Phe 705 710 715 720 Asp Pro Lys Lys His Lys Tyr Asp Ala Glu Tyr Tyr Ile Glu Asn Gln 725 730 735 Val Leu Pro Ala Val Glu Arg Ile Leu Arg Ala Phe Gly Tyr Arg Lys 740 745 750 Glu Asp Leu Arg Tyr Gln Lys Thr Lys Gln Val Gly Leu Gly Ala Trp 755 760 765 Leu Lys Phe 770 <210> SEQ ID NO 5 <211> LENGTH: 19 <212> TYPE: DNA <213> ORGANISM: artificial sequence <220> FEATURE: <221> NAME/KEY: primer <222> LOCATION: (1)..(19) <223> OTHER INFORMATION: Direct primer Aa <400> SEQUENCE: 5 tccggttgat cctgccgga 19 <210> SEQ ID NO 6 <211> LENGTH: 18 <212> TYPE: DNA <213> ORGANISM: artificial sequence <220> FEATURE: <221> NAME/KEY: primer <222> LOCATION: (1)..(18) <223> OTHER INFORMATION: Reverse primer 23Sa <400> SEQUENCE: 6 ctttcggtcg cccctact 18 <210> SEQ ID NO 7 <211> LENGTH: 29 <212> TYPE: DNA <213> ORGANISM: artificial sequence <220> FEATURE: <221> NAME/KEY: primer <222> LOCATION: (1)..(29) <223> OTHER INFORMATION: Direct primer GE23DIR <400> SEQUENCE: 7 tggggcatat gataatcgat gctgattac 29 <210> SEQ ID NO 8 <211> LENGTH: 35 <212> TYPE: DNA <213> ORGANISM: artificial sequence <220> FEATURE: <221> NAME/KEY: primer <222> LOCATION: (1)..(35) <223> OTHER INFORMATION: Reverse primer GE23REV <400> SEQUENCE: 8 gacatcgtcg actctagaac ttaagccatg gtccg 35 <210> SEQ ID NO 9 <211> LENGTH: 21 <212> TYPE: DNA <213> ORGANISM: artificial sequence <220> FEATURE: <221> NAME/KEY: primer <222> LOCATION: (1)..(21) <221> NAME/KEY: primer <222> LOCATION: (1)..(21) <223> OTHER INFORMATION: primer Pyrococcus Sp GE5 <400> SEQUENCE: 9 tcaccttagg gttgcccata a 21 <210> SEQ ID NO 10 <211> LENGTH: 21 <212> TYPE: DNA <213> ORGANISM: artificial sequence <220> FEATURE: <221> NAME/KEY: primer <222> LOCATION: (1)..(21) <221> NAME/KEY: primer <222> LOCATION: (1)..(21) <223> OTHER INFORMATION: primer Pyrococcus Sp. GE23 <400> SEQUENCE: 10 tgggcataaa agtcagggca g 21 

What is claimed is:
 1. A DNA polymerase purified from the strain of archaeobacteria of the genus Pyrococcus sp. GE 5 encoded by the nucleotide sequence shown in SEQ ID NO:
 3. 2. A DNA polymerase purified from the strain of archaeobacteria of the genus Pyrococcus sp. GE 23 encoded by the nucleotide sequence shown in SEQ ID NO:
 1. 3. A thermostable purified DNA polymerase whose amino acid sequence is shown in SEQ ID NO:2.
 4. A thermostable purified DNA polymerase whose amino acid sequence is shown in SEQ ID NO:4. 